Here’s A “D” You’ll Want on Your Report Card

Vitamin D is a critical building block for ensuring strong bones and helping prevent or mitigate a variety of diseases that affect us as we age. Vitamin D helps our body absorb calcium, one of the main building blocks of bone. Vitamin D also plays a role in keeping our nervous, muscle, and immune systems healthy.

We can get vitamin D in three ways: through our skin, from our diet, and from supplements. Our body forms vitamin D naturally after exposure to sunlight. But too much sun exposure can lead to skin aging and skin cancer, so many people try to get their vitamin D from other sources.

It’s important to take steps now so that bones will be healthy and strong throughout our lifetime. That’s especially critical in the childhood and teen years to avoid osteoporosis and other bone problems later in life. Osteoporosis is a condition in which bones become softer and fragile, making them fracture or break much easier.

We build strong bones by getting enough calcium and weight-bearing physical activity during the tween and teen years, when bones are growing their fastest. Young people in this age group have calcium needs that they can’t make up for later in life. In the years of peak skeletal growth, teenagers build more than 25 percent of adult bone. By the time teens finish their growth spurts around age 17, 90 percent of their adult bone mass is established.

The Role of Calcium in Building Healthy Bones

Our body continually removes and replaces small amounts of calcium from our bones. If it removes more calcium than it replaces, our bones will become weaker and have a greater chance of breaking. By getting lots of calcium when we’re young, we can make sure our body doesn’t have to take too much from its bones, where calcium is stored. After age 18 we can only maintain what is already stored to help our bones stay healthy.

Calcium is found in a variety of foods. Low-fat and fat-free milk and other dairy products are great sources of calcium. Tweens and teens can get most of their daily calcium from three cups of low-fat or fat-free milk, but they also need additional servings of calcium to get the 1,300 mg necessary for strong bones. In addition:

Low-fat and fat-free milk has lots of calcium with little or no fat

The calcium in low-fat and fat-free milk and dairy products is easy for the body to absorb and in a form that gives the body easy access to the calcium

Low-fat and fat-free milk has added vitamin D, which is important for helping our body better absorb calcium

In addition to calcium, milk and dairy products provide other essential nutrients that are important for optimal bone health and development.

Other good sources of calcium include dark green, leafy vegetables such as spinach, broccoli and bok choy. There also are foods with calcium added, such as calcium-fortified tofu, orange juice, soy beverages, and breakfast cereals or breads. Adults or youth who can’t process lactose can take calcium supplements but should check with their physicians to ensure compatibility with other medicines or conditions.

Bones are living tissue. Weight-bearing physical activity causes new bone tissue to form, which makes bones stronger. This kind of physical activity also makes muscles stronger. When muscles push and tug against bones during physical activity, bones and muscles become stronger. So there’s much we can do at any age to ensure strong, healthy bones, but it begins with awareness, and is fortified through diet and physical exercise.

Warning Signs of Vitamin D Deficiency

Vitamin D deficiency can lead to a loss of bone density, which can contribute to osteoporosis and fractures. Severe vitamin D deficiency can also lead to other diseases. In children, it can cause rickets. Rickets is a rare disease that causes the bones to become soft and bend. African American infants and children are at higher risk of getting rickets. In adults, severe vitamin D deficiency leads to Osteomalacia, which causes weak bones, bone pain, and muscle weakness.

Additionally, researchers are studying vitamin D for its possible connections to several medical conditions, including diabetes, high blood pressure, cancer, and autoimmune conditions such as multiple sclerosis.

Some people are more prone to vitamin D deficiencies. They include:

Older adults, because skin doesn’t make vitamin D when exposed to sunlight as efficiently as when we were young, and our kidneys are less able to convert vitamin D to its active form

People with dark skin, which has less ability to produce vitamin D from the sun

People with disorders such as Crohn’s disease or celiac disease who don’t handle fat properly, because vitamin D needs fat to be absorbed

People who are obese, because their body fat binds to some vitamin D and prevents it from getting into the blood

People who have had gastric bypass surgery

People with osteoporosis

People with chronic kidney or liver disease

People with hyperparathyroidism (too much of a hormone that controls the body’s calcium level)

People with some lymphomas, a type of cancer

People who take medicines that affect vitamin D metabolism, such as cholestyramine (a cholesterol drug), anti-seizure drugs, glucocorticoids, antifungal drugs, and HIV/AIDS medicines.

How to Get More Vitamin D in Our Bodies

There are a few foods that naturally have some vitamin D. These include

Fatty fish such as salmon, tuna, and mackerel

Beef liver

Cheese

Mushrooms

Egg yolks

We can also get vitamin D from fortified foods. Food labels list whether a food has vitamin D. Foods that often have added vitamin D include

Milk

Breakfast cereals

Orange juice

Other dairy products, such as yogurt

Soy drinks

Vitamin D is in many multivitamins. There are also vitamin D supplements, both in pills and a liquid for babies. If you have vitamin D deficiency, the treatment is with supplements. Check with your health care provider about how much you need to take, how often you need to take it, and how long you need to take it.

Getting too much vitamin D (known as vitamin D toxicity) can be harmful. Signs of toxicity include nausea, vomiting, poor appetite, constipation, weakness, and weight loss. Excess vitamin D can also damage the kidneys. Too much vitamin D also raises the level of calcium in our blood. High levels of blood calcium (hypercalcemia) can cause confusion, disorientation, and problems with heart rhythm.

Most cases of vitamin D toxicity happen when someone overuses vitamin D supplements. Excessive sun exposure doesn’t cause vitamin D poisoning because the body limits the amount of this vitamin it produces, but as mentioned earlier, too much sun exposure can lead to skin cancer and premature aging, so moderation is important.

Talk with your health care provider if you are at risk for vitamin D deficiency. There is a simple blood test which can measure how much vitamin D is in our body. Take steps now to ensure strong bones and better health later in life, essentially through a proper diet and exercise.